Gamma-Hydroxybutyrate Concentrations in the Blood of Impaired Drivers, Users of Illicit Drugs, and Medical Examiner Cases

Gamma-hydroxybutyrate (GHB) was determined in blood samples from impaired drivers, people arrested for petty drug offenses (non-traffic cases), and GHB-related deaths. The method of analysis involved conversion of GHB into gamma-butyrolactone and determination of the latter by gas chromatography with a flame ionization detector, and with gamma-valerolactone as the internal standard. The mean and median concentrations of GHB in blood from impaired drivers (N = 473) were 90 and 84 mg/L, respectively, and offenders were predominantly men (96%) with an average age of 26 year (range 15–50 year). In 185 cases, GHB was the only drug present in blood at mean and median concentrations of 92 and 86 mg/L, respectively. People arrested for petty drug offenses (N = 1061) had slightly higher GHB concentrations in their blood: median 118 mg/L for men and 111 mg/L for women. In GHB-related deaths (N = 33), the mean and median concentrations were considerably higher: 307 mg/L and 190 mg/L, respectively, and the highest was 2200 mg/L. The typical signs of drug influence noted by the arresting police officers included sedation, agitation, slurred speech, irrational behaviour, jerky movements, and spitting. The short elimination half-life of GHB means that the concentrations in blood decrease rapidly and are probably a lot lower than at the time of driving, which was 30–90 min earlier.